Hard to summarize the difference in a sentence or two, as there are all kinds of factors at play: the type of oak the barrel is made from (different types give different flavours); the amount of charring or "toast" the barrels have been given (the more toast, the smokier and more caramelized the flavour imparted to the wine); the barrels' age (the flavours imparted by the barrels diminish from filling to filling as the wine leaches the wood and deposits tartrate crystals on its surface); the barrels' size (the smaller the barrel, the higher the ratio of wood to wine); and so on. Also, barrels are not airtight -- they allow a slow transfer of oxygen through the planks (though, again, the degree is determined by the skill of the cooper, the barrel maker, and the porosity of the wood) -- which slightly oxidizes the wine, among other things smoothing its sharp edges. And, of course, the wood adds its own flavours, tannins and other substances to the wine. Vanilla is a common aroma and flavour of oak, along with the scent and taste of -- duh -- wood.

To avoid being overwhelmed by this treatment requires a wine of some substance, so barrel-aged Chardonnays tend to be richer and more flavourful to start with.

Chardonnays not made or aged in barrels are usually fermented and held in vats made from stainless steel, concrete, glass-lined concrete, etc. Obviously, there is no interaction of wood and wine (unless the winemaker drops some oak planks or chips into the vat). And, oxygen transfer is minimized if not for all intents and purposes eliminated. The result tends to be a purer (in the sense of less adulterated), often sharper and sometimes less complex expression of Chardonnay, especially since the wine is often lighter-weight to begin with.

We tried the oaked as well as the unoaked. I suppose it's a matter of taste, of course, but we prefered the unoaked. It tasted sweeter but the thought it was 'natural' might have been a factor. Thanks to you all for the infos.

Historically, and even now, Oak is used by *some* wine-makers to disguise the flavor of the wine itself, rather like putting a heavy garlic cream sauce on a poor piece of meat to disguise that this is a fairly poor, perhaps past its time steak.

Ideally, oak is used to assist in flavoring the wine, more like a light marinade than a heavy sauce. It should not dominate, but merely accent some of the wine's qualities.

French oak typically is a more seasoned older oak than American oak (we're talking barrels here), and will impart less of a strong odour/flavour to the wine. California has really messed with the reputation of Oak by waaaaay over-oaking a lot of cheap wine, not to mention that a certain portion of the population who don't really like "wine" like to drink over-oaked dry "light" white wines.

Now me, I've only gotten more sensitive to Oak as I get older, and frankly I'm at the point where any wine which is dominated by the oak is not on my to drink list. Consquently, as a rule of thumb I prefer French chardonnay to New Zealand and New Zealand to Australian and Australian to Californian (though there are notable exceptions - good and bad).

One of these exceptions would be Mayacamas chardonnay, from California. And I really kind of hate to mention these people because frankly there isn't enough Mayacamas to go around anyway, and so popularity of it hurts me personally. Anyway, they're an unoaked chardonnay and one of my top 5 chardonnays in the world.

Aside:And no Maggie, I wouldn't call concrete "porous", not in the way it is used in vats.

TY, fussy. I've never had the opportunity to see concrete vats; only visited wineries that use SS.

Btw, when you say you've become more sensitive to oak, do you mean you've developed an allergy or other physical reaction, or instead that the aromas/flavors associated with it have become overbearing?

A FEW ADDITIONS to the overall excellent comments you've already received.

Think of the winemaking as cooking, and the use of oak as part of a chef's pantry.

Say you're making soup. The specific type of soup would be the type of grape(s) the winemaker is using; in this case, Chardonnay.

OK, so you slice and dice, chop your veggies, toss them in a stock pot, put the pot on the stove top and go away for four hours . . . what do you have? A bunch of raw, uncooked veggies sitting in cold water. You forgot to turn on the gas.

This is analogous to keeping your wine in stainless steel. Very little happens to the wine, as stainless is inert, and the flavors of the newly fermented wine change very little.

OK, so now you turn on the stove, and the water boils; the veggies cook, and eventually your soup is done. Oak is akin (in this analogy) to turning on the gas. The wine changes as it AGES in oak; something it doesn't do when it is STORED in stainless steel tanks. Aging in oak changes the wine.

But this isn't what a chef does, is it? The chef will also add salt, pepper, different spices, various herbs, etc. New(er) wook will have its own inherent "bouquet garnis" of flavors it adds to the wine. Just as a trusty old stockpot is still perfect for cooking the soup, a 10-, 20-, 100-year old barrel is still perfect for aging the wine. However, an old barrel will not have its own "herbs and spices" to contribute. So winemakers use new(er) wood.

And it doesn't have to be oak. Certainly oak dominates the wine world, but various woods are used around the world. But each oak is different, depending upon where the tree was grown; and each cooper (barrel maker) treats the wood a little differently -- so that (e.g.) a Limousin barrel from Damy will have a different character, a different effect upon the same wine than would a Limousin oak barrel made by Radoux, etc., etc.

Most winemakers will use barrels from a variety of different coopers and/or different forests of origin to layer in additional flavors to the wine. But most wineries will ALSO keep many older barrels (known as "neutral wood") around, and use them on a regular basis. Why?

Because if the first thing you taste is the salt, the chef screwed up the soup. You ordered vegetable soup, not salt soup, but it's the salt that dominates??? Bad cooking. If the oak dominates, bad winemaking. Oak is a "spice" in the winemaker's cabinet. The wine is, in this case, Chardonnay; it isn't "not oak wine."

What constitutes too much oak? Ah, there's the problem -- it's up to the individual. Some people may think Chateau Cache Phloe Chardonnay is too oaky; others may think it's perfect.

* * * * *

By the way, some wineries will use oak chips in the wine. These are often like giant tea bags, and they are dropped into a stainless steel tank -- often, though not always by any means, Chardonnay. The oak "tea bag" steeps in the tank of wine and adds an oak flavor.

This is NOT AGING. This is adding oak flavor. But wine AGES in oak; it doesn't in stainless. So, this is like adding salt to that mixture of diced veggies and cold water in the stock pot when you haven't turned on the gas -- you still haven't cooked the soup . . .